Three state magnet valve

ABSTRACT

A three-state magnet valve for control of fluid flow engageable with a source of fluid pressure for connecting the three-state magnet valve to a source of fluid pressure. The three-state magnet valve also has an application pilot solenoid valve having a fluid connection to a source of fluid pressure and is electrically connectable to a control module. The three-state magnet valve further has an application solenoid valve having a fluid connection to a source of fluid pressure and to an application pilot solenoid valve and a braking device. The application solenoid valve is also electrically connectable to a control module. The application solenoid valve is able to initiate a braking application upon receipt of a fluid signal from the application pilot solenoid valve and an electrical signal from a control module. The three-state magnet valve further has a release pilot solenoid valve having a fluid connection to a source of fluid pressure and to the application solenoid valve and is electrically connectable to a control module. The three-state magnet valve also has a release solenoid valve having a fluid connection to an exhaust to atmosphere and to the application solenoid valve and to the release pilot solenoid valve and to a braking device. The release solenoid valve is electrically connectable to a control module. The release solenoid valve is able to exhaust fluid pressure to atmosphere upon receipt of a fluid pressure signal from the release pilot solenoid valve and an electrical signal from a control module thereby exhausting fluid pressure from said braking device.

FIELD OF THE INVENTION

[0001] The present invention generally relates to a fluid control valve. More particularly, the invention relates to a fluid control valve that utilizes several solenoid valves to achieve three states of operation.

BACKGROUND OF THE INVENTION

[0002] An ANSI schematic of the operation of the prior art R-10 magnet valve is given in FIG. 2. The R-10 magnet valve described below is manufactured and sold by Westinghouse Air Brake Technologies Corporation. The R-10 magnet valve consists of two 2-way Air Flow Management Valves, one 3-way Application Pilot Valve, and one 3-way Release Pilot Valve. The operation cycle of the R-10 magnet valve is described below:

[0003] When all pilot valves are de-energized a supply pressure from reservoir enters the unit and pilots the application valve open, and the supply pressure flows to a brake cylinder.

[0004] When the application pilot is energized, thereby restricting the application valve to the choked port. The brake cylinder pressure is sustained.

[0005] When the release pilot is energized, the release pilot pressure is exhausted and the release valve is forced open by the brake cylinder pressure. The choked supply port flows to exhaust also.

[0006] When the application pilot is de-energized and while the release pilot remains energized the application pilot pressure is exhausted and the application valve opens. This allows the supply pressure to flow unrestricted through the exhaust port.

[0007] An ANSI schematic of the operation of the prior art N-7-D Magnet Valve is given in FIG. 3. The N-7-D magnet valve described below is also manufactured and sold by Westinghouse Air Brake Technologies Corporation. The N-7-D magnet valve consists of one 2-way Air Flow Management Valve, one 3-way Air Flow Management Valve, one 3-way Application Pilot Valve, and one 3-way Release Pilot Valve. The operation cycle of the N-7-D Magnet Valve is described below:

[0008] With all pilot valves de-energized a supply pressure flows directly into brake cylinder from reservoir. Pilot pressure is supplied independently.

[0009] With the application pilot energized it closes the supply pressure off from the brake cylinder and brake cylinder pressure exhausts.

[0010] With the release pilot energized the exhaust port is closed off from brake cylinder, thus holding brake cylinder pressure constant.

[0011] With the application pilot de-energized while the release pilot remains energized the application pilot pressure is exhausted, causing the application valve to close off exhaust from brake cylinder thus allowing supply pressure to flow to brake cylinder.

SUMMARY OF THE INVENTION

[0012] In one aspect, the invention generally features a three-state magnet valve for control of fluid flow. The three-state magnet valve has a means engageable with a source of fluid pressure for connecting the three-state magnet valve to a source of fluid pressure. The three-state magnet valve also has an application pilot solenoid valve having a fluid connection to a source of fluid pressure and is electrically connectable to a control module. The three-state magnet valve further has an application solenoid valve having a fluid connection to a source of fluid pressure and to an application pilot solenoid valve and a braking device. The application solenoid valve is also electrically connectable to a control module. The application solenoid valve is able to initiate a braking application upon receipt of a fluid signal from the application pilot solenoid valve and an electrical signal from a control module. The three-state magnet valve further has a release pilot solenoid valve having a fluid connection to a source of fluid pressure and to the application solenoid valve and is electrically connectable to a control module. The three-state magnet valve also has a release solenoid valve having a fluid connection to an exhaust to atmosphere and to the application solenoid valve and to the release pilot solenoid valve and to a braking device. The release solenoid valve is electrically connectable to a control module. The release solenoid valve is able to exhaust fluid pressure to atmosphere upon receipt of a fluid pressure signal from the release pilot solenoid valve and an electrical signal from a control module thereby exhausting fluid pressure from said braking device.

[0013] In another aspect, the invention generally features a method for wheel slip control using a three-state magnet valve. The method is comprised of the steps of generating a signal in a control module and giving a command signal to at least one of a plurality of solenoid valves that allows a source pressure to be at least one of applied to, exhausted from and held stable at a braking device based on said signal generated.

OBJECTS OF THE INVENTION

[0014] It is, therefore, one of the primary objects of the present invention to provide a three state magnet valve consisting of two 2-way valves without the possible failure mode of venting the supply and delivery to exhaust.

[0015] It is, therefore, another object of the present invention to provide a three state magnet valve that allows the release pilot valve to have two functions.

[0016] It is, therefore, yet another object of the present invention to provide a three state magnet valve that allows the release pilot valve to release brake cylinder pressure to exhaust.

[0017] It is, therefore, still a further object of the present invention to provide a three state magnet valve that offers an override that closes the application valve regardless of the state of the application pilot valve, eliminating the possibility of venting the supply pressure to exhaust unintentionally.

[0018] It is, therefore, even another object of the present invention to provide a three state magnet valve that is designed to retain the simplicity, size, and cost of using two 2-way valves while adding value to its function.

[0019] In addition to the above-described objects and advantages of the three state magnet valve, various other objects and advantages of the present invention will become more readily apparent to the persons who are skilled in the same and related arts from the following more detailed description of the invention, particularly, when such description is taken in conjunction with the attached drawing figures and the appended claims.

DESCRIPTION OF THE DRAWING

[0020]FIG. 1 is an ANSI schematic of the operation of the presently preferred invention.

[0021]FIG. 2 is an ANSI schematic of the operation of the prior art R-10 Magnet Valve.

[0022]FIG. 3 is an ANSI schematic of the operation of the prior art N-7-D Magnet Valve.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

[0023] Prior to proceeding to a much more detailed description of the presently preferred invention, it should be noted that identical components which have identical functions have been identified with identical reference numerals throughout the several views illustrated in the drawing figures for the sake of clarity and understanding of the invention.

[0024] Referring initially to FIG. 1 a three state magnet valve constructed according to the presently preferred invention is generally indicated by reference numeral 10. The three state magnet valve 10 generally includes an application pilot solenoid valve 12, a release pilot solenoid valve 14, an application solenoid valve 16, and a release solenoid valve 18, a means engageable with a source of fluid supply 22, a fluid connection 24 to a braking device, and an exhaust to atmosphere 26.

[0025] An ANSI schematic of the operation of the presently preferred invention is produced in FIG. 1 for reference. The three state magnet valve 10 of the present invention consists of a means engageable with a source of fluid pressure 22 for connecting the three-state magnet valve to the source of fluid pressure, the means 22 preferably being a port.

[0026] The application pilot solenoid valve 12 has a fluid connection to the source of fluid pressure and is electrically connectable to a control module (not shown), the application pilot solenoid valve preferably being of the 3-way normally closed type.

[0027] The application solenoid valve 16 has a fluid connection to the source of fluid pressure, to the application pilot solenoid valve 12, and to a braking device (preferably a brake cylinder, not shown), and is electrically connectable to a control module. The application solenoid valve 16 is preferably of the 2-way normally closed type. The application solenoid valve 16 is able to initiate a braking application by allowing source pressure to be transmitted to a fluid connection 24 to a braking device upon receipt of a fluid signal from the application pilot solenoid valve 12, and an electrical signal from a control module.

[0028] The release pilot solenoid valve 14 has a fluid connection to the source of fluid pressure and to the application solenoid valve 16 and is electrically connectable to a control module. The release pilot solenoid valve 14 is preferably of the 3-way normally open type.

[0029] The release solenoid valve 18 has a fluid connection to an exhaust to atmosphere 26 and to the application solenoid valve 16 and to the release pilot solenoid valve 14 and to the braking device and is electrically connectable to a control module. The release pilot solenoid valve 14 is preferably of the 2-way normally open type. The release solenoid valve 18 is able to exhaust fluid pressure to atmosphere upon receipt of a fluid pressure signal from the release pilot solenoid valve 14 and an electrical signal from a control module thereby exhausting fluid pressure from the braking device (not shown) through a fluid connection to an exhaust to atmosphere 26.

[0030] The following is a description of the general operation cycle of this three state magnet valve when used as a wheel slip control valve:

[0031] 1. Application pilot solenoid 12 and release pilot solenoid 14 are de-energized by a control module. Source pressure then is allowed to enter the three state magnet valve 10 through the application pilot solenoid 12 and pilots the application solenoid 16 open. The source pressure is allowed to flow to brake cylinder (not shown) through the fluid connection 24 to a braking device.

[0032] 2. The application pilot solenoid 12 is energized by a control module, allowing the pilot pressure from application solenoid 16 to exhaust through the release solenoid 18 and its connection to an exhaust to atmosphere. The application solenoid 16, in turn, closes and holds the pressure steady at the brake cylinder (not shown).

[0033] 3. The release pilot solenoid 14 is energized by a control module, allowing pilot pressure to be supplied to the release solenoid 18. This opens the release solenoid 18, which exhausts brake cylinder (not shown) pressure through its connection to an exhaust to atmosphere. Energizing release pilot solenoid 14 also applies pilot pressure to the application solenoid 16. This pilot pressure holds the application solenoid 16 closed, keeping the source pressure from exhausting to atmosphere.

[0034] 4. The release pilot solenoid 14 is energized by a control module and application pilot solenoid 12 is not energized by a control module. In this state the pilot pressure would be holding the application solenoid 18 open initially, while the spring inside the release solenoid 18 is holding the release solenoid 18 closed. Then, after the control module energizes the release pilot solenoid 14, pilot pressure forces the application solenoid 16 closed and the release solenoid 18 open. This allows the pressure in the brake cylinder (not shown) to be exhausted through the release solenoid and its connection to an exhaust to atmosphere, while keeping the source pressure from exhausting to atmosphere.

[0035] States 3 and 4 produce the same result. Brake cylinder pressure exhausts to atmosphere and source pressure is retained. Therefore the valve has only three different states.

[0036] While the present invention has been described by way of a detailed description of a particularly preferred embodiment, it will be readily apparent to those of ordinary skill in the art that various substitutions of equivalents may be affected without departing from the spirit or scope of the inventions set forth in the appended claims. 

I claim:
 1. A three-state magnet valve for control of fluid flow, said three-state magnet valve comprising: (a) a means engageable with a source of fluid pressure for connecting said three-state magnet valve to said source of fluid pressure; (b) an application pilot solenoid valve having a fluid connection to said source of fluid pressure and electrically connectable to a control module; (c) an application solenoid valve having a fluid connection to said source of fluid pressure and to said application pilot solenoid valve and a braking device and electrically connectable to such control module, said application solenoid valve initiating a braking application upon receipt of a fluid signal from said application pilot solenoid valve and an electrical signal from such control module; (d) a release pilot solenoid valve having a fluid connection to said source of fluid pressure and to said application solenoid valve and electrically connectable to such control module; and (e) a release solenoid valve having a fluid connection to an exhaust to atmosphere and said application solenoid valve and said release pilot solenoid valve and said braking device and electrically connectable to such control module, said release solenoid valve exhausting fluid pressure to atmosphere upon receipt of a fluid pressure signal from said release pilot solenoid valve and an electrical signal from such control module thereby exhausting fluid pressure from said braking device.
 2. A three-state magnet valve according to claim 1, wherein said braking device is a brake cylinder.
 3. A three-state magnet valve according to claim 1, wherein said means engageable with a source of fluid pressure for connecting said three-state magnet valve to said source of fluid pressure is a port.
 4. A three-state magnet valve according to claim 1, wherein at least one of said solenoid valves is of the 3-way, normally open type.
 5. A three-state magnet valve according to claim 1, wherein at least one of said solenoid valves is of the 3-way, normally closed type.
 6. A three-state magnet valve according to claim 1, wherein at least one of said solenoid valves is of the 2-way, normally open type.
 7. A three-state magnet valve according to claim 1, wherein at least one of said solenoid valves is of the 2-way, normally closed type.
 8. A method for wheel slip control using a three-state magnet valve, said method comprising the steps of: (a) generating a signal in a control module; (b) giving a command signal to at least one of a plurality of solenoid valves that allows a source pressure to be at least one of applied to, exhausted from and held stable at a braking device based on said signal generated.
 9. A method for wheel slip control using a three-state magnet valve according to claim 8, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to de-energize said application pilot and said release pilot solenoid valves and allow said source of fluid pressure to enter said three state magnet valve and pilot at said application solenoid valve open to allow said source of fluid pressure to flow to said braking device.
 10. A method for wheel slip control using a three-state magnet valve according to claim 8, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves which energizes said application pilot solenoid valve and allows a pilot pressure from said application solenoid valve to exhaust to atmosphere.
 11. A method for wheel slip control using a three-state magnet valve according to claim 10, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to allow said application solenoid valve to close and hold said source pressure steady at such braking device.
 12. A method for wheel slip control using a three-state magnet valve according to claim 8, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid valve and allow a pilot pressure to be supplied to said release solenoid.
 13. A method for wheel slip control using a three-state magnet valve according to claim 12, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to open said release solenoid and allow a fluid pressure to exhaust from said braking device to atmosphere.
 14. A method for wheel slip control using a three-state magnet valve according to claim 13, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to apply a pilot pressure to said application solenoid and allow said application solenoid to be closed and prevent said source pressure from exhausting to atmosphere.
 15. A method for wheel slip control using a three-state magnet valve according to claim 8, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid valve and not energize said application pilot solenoid valve and allow a pilot pressure to hold said application solenoid valve open initially.
 16. A method for wheel slip control using a three-state magnet valve according to claim 15, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to bias said release solenoid valve and hold said release solenoid valve closed.
 17. A method for wheel slip control using a three-state magnet valve according to claim 16, wherein said command signal in step (b) is communicated to at least one of said plurality of solenoid valves to energize said release pilot solenoid and allow a pilot pressure to force said application solenoid valve closed and said release solenoid valve open allowing a fluid pressure to exhaust to atmosphere from said braking device while holding said source pressure steady. 